GPIO subsystem is a very important subsystem that allows the users to interface the board with sensors and other peripherals and allow interaction with real world.Pocket Beagle and Beaglebone black are the two most popular variants among the enthusiasts.
There might be situations when your Beaglebone image might not bootup or you might be playing around with uboot , MLO/SPL or might have added a new static module to kernal that might be stopping the image to boot. In all such cases you might want to peek inside the messages sent on the serial console.
There are 2 variants of compilers namely clpru and pru-gcc available which allows the user to write a c, c++ code to interface peripherals with PRU. There are 2 32 bit registers namely R30 and R31 writing value to the bits of these resistors controls the output value on the pin.
There are two improtant sub systems in the AM335X the ARM subsystem and the PRU sub system To get the best out of both the worlds one need to setup a communication mechanism between two.
Beaglebone boards are an example of Heterogenous computing systems . It refers to systems that use more thatn one kind of processors or cores.
So far it has been a intresting journey. I could make the Shift registers apper as gpio lines, acces through character driver and control the ICs. But it is a crutial juncture , I need to figure out the next sets. I have been thinking of a SPI interface since what i am doing in the PRU is bitbanging SPI